The present invention relates to a thin switch employed for various types of control apparatuses, an FA (factory automation) apparatus, a vending machine, a ticket-vending machine, an information apparatus, a household electric appliance, a medical operating apparatus or the like and a display panel provided with a switch employing the same.
Thin switches and display panels provided with switches employing the same, have already been proposed. As an example thereof, there is a thin switch having a structure obtained by superposing a thin switch on a display panel having an information display function.
This thin switch comprises at least one transparent or translucent pushbutton provided on a transparent or translucent touch panel (touch switch). This pushbutton rotates at a constant stroke for pressing and turning on the touch panel. As the touch panel, a resistor film type one is typically employed.
However, it cannot be said that the light transmittance of the touch panel employed for this conventional thin switch is sufficiently high but reflection or attenuation of light takes place when light is transmitted through the touch panel. Therefore, visibility of the display contents of the display panel lowers due to the presence of this touch panel.
In the touch panel, the operating temperature thereof is generally about 0xc2x0 C. to 50xc2x0 C., and the storage temperature is generally about xe2x88x9220xc2x0 C. to 60xc2x0. Considering outdoor use or the environment in a transportation stage (for example, transportation by air mail, by surface mail or the like), it is definitely not excellent in environmental resistance.
Further, the touch panel is a switch utilizing contact between oppositely arranged transparent electrodes. Therefore, a contact part deteriorates due to use over long years, and this serves as the cause reducing the life.
In the touch panel, further, it is difficult to determine which pushbuttons are pressed when at least two points are simultaneously pressed, i.e., when a plurality of pushbuttons are simultaneously pressed, due to its structure whether the same is digital or analog.
The principal object of the present invention is to provide a thin switch capable of thinning the aforementioned thin switch, capable of attaining improvement of visibility of display contents of a display panel, having resistance against various environments, capable of attaining a long life, and capable of determining which pushbuttons are pressed also when a plurality of pushbuttons are simultaneously pressed and a display panel provided with a switch employing the same.
Accordingly, the present invention is directed to a thin switch, used in superposition on a display panel having an information display function in order to attain the aforementioned principal object, comprising a pushbutton movable in a press direction at a constant stroke and transparent or translucent, a bridge arranged in the vicinity of outer sides of at least two opposite edges of the pushbutton, a first permanent magnet provided on an end of the pushbutton on the side facing the bridge, a magnetic body or a second permanent magnet provided on an upper portion of the bridge opposed to the first permanent magnet and a Hall element integrated circuit provided on the bridge on the side facing the first permanent magnet in correspondence to the pushbutton, while the magnetic body or the second permanent magnet structures return means generating returning force in the pushbutton by attractive force generated between the same and the first permanent magnet while causing a click feeling when pressing the pushbutton along with the first permanent magnet, and the Hall element integrated circuit has a Hall element and a determination circuit determining whether or not its Hall voltage is larger than a threshold, for detecting change of a magnetic field by the first permanent magnet provided on the pushbutton when pressing the corresponding said pushbutton and changing an output state.
Due to this structure, the permanent magnet of the pushbutton and the Hall element integrated circuit corresponding thereto structure contactless switches respectively without employing a touch panel, whereby the aforementioned problem resulting from the touch panel can be solved while making the best use of such characteristics that thinning is possible and a stroke feeling as well as a click feeling can be obtained. At this point, the stroke feeling means a sense of pushing, and the click feeling is such a sense that pushing abruptly lightens halfway.
In other words, no touch panel lowering visibility intervenes between the pushbutton and the display panel located under the same dissimilarly to the aforementioned prior art, whereby visibility of the display contents of the display panel improves. Further, the pushbutton can be approached to the lower display panel due to the absence of the touch panel so that parallax in the case of obliquely viewing the display panel lessens, whereby visibility of the display contents of the display panel improves as compared with the case of employing a touch panel also from this point of view.
Further, the Hall element integrated circuit is structured by a semiconductor element, completely of a static type and has no mechanically moving part such as a transparent thin plate of a touch panel, whereby the ranges of the operating temperature and the storage temperature thereof are wide as compared with the touch panel and hence environmental resistance improves as compared with the case of employing the touch panel.
In addition, a non-contact detection system by combination of the Hall element integrated circuit and the permanent magnet is employed, whereby there is no deteriorating part and hence the life lengthens as compared with the case of employing the touch panel. Reliability of the switch also rises.
Further, the Hall element integrated circuit is provided in correspondence to one or more pushbuttons, whereby which pushbuttons are pressed individually or simultaneously can be reliably determined.
In this thin switch, further, the permanent magnet provided on the pushbutton serves both as the permanent magnet for the return means and the permanent magnet for changing the output state of the Hall element integrated circuit, whereby no extra permanent magnet may be provided exclusively for the Hall element integrated circuit. Therefore, reduction of the number of components, reduction of the number of assembling steps, miniaturization/weight reduction and reduction of the cost can be thereby attained.